Unloader of magnetically attracted parts



Oct. 16, 1956 E. w. ATWOOD 2,765,837

UNLOADER OF MAGNETICALLY ATTRACTED PARTS Filed June 17, 1955 [ar/ Vl/ Aft/V000 I INVENTOR.

BY llel f ATTORNEY United States Patent UNLOADER OF MAGNETICALLY ATTRA'CTED PARTS Earl W. Atwood, Galena Park, Tex.

Application June 17, 1955, Serial No. 516,270

4 Claims. (Cl. 209-2159 Discarded tinned sheet steel cans are often picked up at city dump grounds for commercial salvage, and equipment sometimes employed consists of a conventional electromagnet suspended above the ground by a power vehicle which travels the dump area and from which accumulated cans are periodically unloaded by stopping the vehicle and interrupting current flow. Unloaded cans are then shoveled by hand into a truck, to be hauled to a shredding and baling plant. To speed up the operation and reduce labor required, it is here proposed to keep the magnet energized without interruption and to continually throw off or unload the magnet of lifted cans, and preferably to direct the thrown-off cans into the hauling truck body. The magnet pickup and throwing assembly can be towed or carried by tihe hauling truck or else mounted on a tractor beside which a haulaway vehicle travels to receive its load. With such equipment, an entire dump area can be cleaned up in a single continuing mechanical operation in merely the time required to transport the magnet over the surface to be worked and with no manual effort other than that for vehicle steering.

The present invention relates to a magnet pickup and unloading assembly suitable for can salvaging operations and for other types of magnet lifting operations, and the invention has for one of its objects an arrangement wherein magnetic materials within the magnetic field are attracted and moved toward the magnet but are intercepted before reaching the pole faces and are mechanically redirected by a centrifugal spinner and propelled with great force outside the magnetic field without ever becoming stuck to the magnet.

A further object of the invention is to provide a simple and inexpensive adaptation of a commercial electromagnet by the addition of a few parts consisting primarily of a drive shaft extending centrally through the magnet core, with drive connection at one end and with its opposite end carrying a spinner disk of nonmagnetic material closely covering the magnet pole faces and spinning at high speed within the magnetic field, together with a collector to cooperate with the spinner at its periphery so that the parts elevated under magnetic force are spun outwardly while so suspended with an inertia force that throws them as directed by the collector in a selected path and beyond the field of magnetic attraction.

Other objects and advantages will become apparent during the course of the following specification having reference to the accompanying drawing, wherein Fig. l is a vertical sectional view of the improved pickup and discharge assembly and Fig. 2 is a bottom plan view of the assembly as viewed on line 2-2 of Fig. 1.

Generally the magnet will be suspended over a bed of material containing magnetic parts to be salvaged and the operation will involve the relative travel of the bed and the magnet with the lower face of the magnet spaced above the bed a distance that the bed surface is well within the magnetic field. Such distance will be on the order of fifteen inches with a standard heavy-duty elecn'omagnet which has been found suitable and which has a diameter 2,766,887 l atented Oct. 16, 1956 of about twenty-five inches and a catalogue rating for average (all-day) lifting capacity in pounds of seventyfive hundred for billets or slabs and one hundred for steel turnings. Structurally the magnet consists of wound coils 1, housed within an annular magnet case 2 whose peripheral wall at its bottom edge provides an outer pole shoe 3 and whose central core 4 at its lower face provides the central pole shoe. A renewable center pole shoe 5 is illustrated in the drawing as being detachably fastened by machine screw studs 6' over the bottom face of the core 4. These fastening studs 6 are replacements for the customary center bolt, whose head seats within a countersunk center opening on the under face of the shoe 5, with the bolt shank extending upwardly through a bore in the core 4 and receiving a securing nut at the upper bolt end.

It is here proposed to rework the center bolt opening in the core 4 to provide upper and lower recesses or pockets for antifriction ball or roller bearing assemblies 6 and 7 which rotatably support a drive shaft 8. At its lower end the drive shaft 8 is threaded and carries a nut 9 of inverted cone or truncated cone shape to provide upwardly and outwardly inclined side surfaces terminating in a base of a size to cover and underlie the face of the center pole shoe 5. Secured by studs 10 to the base of and as a subassembly unit with the nut 9 is a plate or disk 11 whose peripheral rim extends to and at least partially underlies the face of the outer pole shoe 3. Both the plate 11 and the nut 9 should be of nonmagnetic material, and for convenience of manufacture the nut 9 may be of brass and the plate 11 of stainless steel.

At its upper end and above the upper face of the magnet case 2 the drive shaft 3 is provided with a coupling flange 12 for attachment with a mating flange 13 on a short shaft 14 projecting downwardly through the Wall of a transfer gear box 15 and carrying a bevel gear 16 housed within the gear box. In mesh with the bevel gear 16 is a bevel gear 17 to be driven from a suitable source such as a power take-off mechanism of a traction vehicle or an electric, hydraulic, or other type of motor 18 assembled as a part of the pickup unit and conveniently mounted on the cover of the coil terminal box 19 formed as a part of the magnet case 2. A drive ratio of the meshing bevel gears 16 and 17 should be selected in accord with the rate of rotation of the power feed shaft in order to impart high speed rotation to the spinner disk assembly. Spinner speeds of approximately 1,350 R. P. M. are contemplated. To suspend the pickup unit, the base 20 of a bracket is secured by bolts 21 over the upper face of the magnet case 2 and it has an upstanding leg 22 to support the transfer case 15 and a pair of upstanding side legs, a fragment of one :of which is shown at 23, and which rise on opposite sides of the transfer case 15 and carry trunnions or eyes to be engaged by cable suspension hooks or the like.

Welded or otherwise supported from the outer pole shoe 3 is a dependent annular skirt or shroud 24 prefer ably but not necessarily of stainless steel or other nonmagnetic material and which extends downwardly for a working distance below the spinner assembly and to a lower edge spaced relation with the surface indicated by a broken line 25 of the bed to be traversed by the pickup assembly. This skirt 24 is a circular wall closely bordering the peripheral rim of the spinner disk 11 and affords a path defining guide leading to a discharge window in the wall 24 and with which is associated a tangentially disposed transfer chute 26 to receive materials thrown off under centrifugal force generated at the spinner disk 11; and to direct them laterally and either into a truck loading conveyor or directly to the hauling truck body. Since the body of the hauling truck will be higher than the dis-- charge window in the skirt 24, the transfer chute 26 can have an upwardly inclined riser and the centrifugal discharge force of the spinner is suflEicient to throw or impeli the materials discharged through the riser and intd the truck body.

In can salvaging operations themagnetic coil receives anuninterrupted supply of electric curre'n't' andduring relative travel ofthe magnet its field exertsa lifting pull on tinca'n's lying at the surface of the ground sufiicient to overcomethe' can gravity-weight so that the cans'rise toward the'l'o'wer faceef the magnet but are intercepted intheir upwa'rd travel by the tapered under surface of the nut 9 and the underside of the spinner disk'il, which" remain uumagnetized and whose rapid revolution forcibly redirects the cans outwardly and impartsto them a centrifugal force,- whereby they skid outwardly andscrub aroundon the guide wall 24 in the direction of rotation indieat 'ed by the arrow in Fig. 2 to thedischarge window, throughwhich they are flung with great inertia force out oh the sem of the magnet and through the collector chute Obviously, the improved structure Will find usefulness 'in fi'eld's other than for salvaging discarded tin cans, as

herein specifically described, and it will be understood that the structure iscapable of such modification as comes within the scope of the appended claims.

What is claimed is:

I. In a device of the character described, a lifting magnet arranged to' be separated by an air space above the ground surface which is within the field of magnetic lines of force, a spinner disk of nonmagnetic material p'osi-t ironed beneath themagnet and within the field thereof and whose under surface constitutes slide 7 contact face for magnetic parts elevated through andsuspended within said air space under magnetic attraction, drive means connected with the nonmagnetic disk and operative tospin the same at high speed sufiicient' to impart centrifugal force and an outward travel to magnetically sus- 4, under magnetic influence and which suspended material receives force from its engagement with the spinner disk to flow outwardly, a cylindrical skirt extending downwardly from the magnet frame and below and in juXtaposed relation with the rim of said disk and in the cen trifugal flow path :of material suspended in the air and against said spinner disk and with which skirt a spinner disk engaged material sweepsduring spinner disk'rotation, said skirt having a discharge opening therein and a collector aligned with the discharge opening to receive magnetic material thrown by'centrifugal force imposed thereon through engagement with the spinner disk. I

3. In a device of the character described, a circular magnet having an annular frame and a central core pro- 'viding pole faces on the underside thereof, a nonmag- V netic spinner disk underlying said pole faces and within the magnetic field,- a drive shaft secured to said spinner V a wardly from contact with the spinner disk, said skirt hav- 7 ing abreak in its circular continuity to provide a side out: let from which the parts inslide contact with the spinner pended parts engaged thereby and a stationary retainer 7 and guide wall bounding'and projecting below the rim of said diskthro'ughout' the major portion of its circumference' and against which said magnetically suspended parts sweep circularly,- said .wallhaving a window through positioning in spaced relation aliove the surface of the diskand projected vertically through the central core to the upper side of the magnet, bearings mounted in the core androtatably supporting said shaft, a power drive connection with the upper end of said shaft for spinning said disk at high speed to impart to parts lifted by the,

magnet through the air and into slide bearing contact with the disk a centrifugal force tending to throw such 7 parts radially beyond the field of the magnet and a collector skirt carried by and dependent from said frame at the rim of the spinner disk in the path of parts thrown outdisk and spun therewith are ejected by centrifugal force imparted through said contact.

4. The method of collecting and loading salvageable tinned cans and other light weight iron scrap lying on the surface of a dump bed, including transporting across the dumpbed' and in co-operative traveling relation a hauling;

body and an el'ectromagnet suspended'above the ground surface for adistance that the magnetic linesof force exarea With such surface within the magnetic field and sep- .arated' from the magnet by an air space, a rotarydrive shaft erite'nding through a vertical bore in the central core of the magnet and being supported by said core, shaft drive means engaging the upper end of the shaft, a nonmagnetic spinner disk-fixed to the lower end of said shaft in covering relation with the underside of said electromagnet for slidable engagement of magnetic material elevated through and held suspended within said air space fend through the air to the ground surface, connecting the storage space of said hauling body with the area within the field of magnetic attraction beneath the suspended magnet by a circular nonmagnetic shroud bounding said area, together with a delivery chute extending tangentially from a side window inthe chute to said body storage space, and driving a spinner plate of nonmagnetic material underlying said magnet in a plane above said chute for slide bearing engagement with the magnet lifted scrap which by reason of such bearing engagement is thrown bodily by centrifugal force outwardly against the shroud and thro'ugh the delivery chute into said body storage space.

References'Cited inthe file of this patent UNITED STATES PATENTS Grondal Feb. 6, 1906 Ullman Apr. 11, 1939 

